The objectives of the proposed research are to obtain a better understanding of the organization and function of adrenal chromaffin vesicles, to purify and characterize the plasma membrane of adrenal medullary cells and to determine interaction between the chromaffin vesicles and plasma membranes which may be involved in the process of secretion. The soluble and membrane-bound forms of bovine adrenal dopamine-beta-hydroyxlase will be purified and their physical, chemical and immunological properties studied to determine whether the enzymes are identical. The chromogranins will be purified by ion exchange and gel chromatography and chemical, physical and immunological studies carried out to establish their interrelationships. The phosphorylation of phosphatedylinositol to form diphosphoinositol by purified chromaffin vesicle membranes will be studied to determine the relationship of their reaction to the ATPase activity. Plasma membranes of adrenal medullary cells will be purified and characterized with respect to their protein and lipid content, their protein components, their adenyl cyclase activity and their cholinergic receptors.